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A novel weld-pool-length monitoring method based on pixel analysis in plasma arc additive manufacturing

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Advances in Manufacturing 2024年第2期12卷 335-348页

作者： Bao-Ri Zhang Yong-hua shi Bionic Robot Research Department Ji Hua LaboratoryFoshan528200GuangdongPeople’s Republic of China Guangdong Provincial Engineering Research Center for Special Welding Technology and Equipment School of Mechanical and Automotive EngineeringSouth China University of TechnologyGuangzhou510640People’s Republic of China

The real-time monitoring of the weld pool during deposition is important for automatic control in plasma arc additive *** obtain a high deposition accuracy,it is essential to maintain a stable weld pool *** this study,a novel passive visual method is proposed to measure the weld pool *** the proposed method,the image quality was improved by designing a special visual system that employed an endoscope and a *** also includes pixel brightness-based and gradient-based algorithms that can adaptively detect feature points at the boundary when the weld pool geometry *** algorithm can also be applied to materials with different solidification *** was performed to measure the real weld pool length in world coordinates,and outlier rejection was performed to increase the accuracy of the ***,tests were carried out on the intersection component,and the results showed that the proposed method performed well in tracking the changing weld pool length and was applicable to the real-time monitoring of different types of materials.

关键词： Plasma arc additive manufacturing(PAAM) Weld pool geometry Gradient analysis Real-time detection

Synthesis of Tin Oxide Through Thermal Decomposition of Sn_2(NH_4)_2(C_2O_4)_3 and Its Gas Sensing Property

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Chemical Research in Chinese Universities 2005年第6期21卷 641-645页

作者： shi Juan WU shi-hua WANG Shu-rong School of Materials Science and Chemical Engineering Tianjin Polytechnic University Tianjin 300160 P. R. China Department of Chemistry Nankai University Tianjin 300071 P. R. China

Nanocrystalline tin oxide samples were prepared by using Sn2 （NH4 ）2 （C2O4）3 as the precursor. The thermal decompositions were respectively conducted at 250,450 and 650 ℃. TG-DTA, XRD, TEM, FTIR were used to characterize the samples. The indirect heating sensors by using these materials as sensitive bodies were fabricated on an alumina tube with Au electrodes and platinum wires. Sensing properties of these sensors were investigated. It was found that the tin oxide sample obtained by thermal decomposition at 450 ℃ has a higher sensitivity to C2H5OH and a higher selectivity to hexane and ammonia than those obtained via the conventional precipitate method and the working temperatures needed were greatly decreased.

关键词： Tin dioxide Thermal decomposition Gas sensing property Selectivity

Slip in Couette flow with pressure gradient:Theoretical and experimental investigation of hydrodynamic characteristics considering slip effect

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Journal of Hydrodynamics 2020年第1期32卷 107-115页

作者： Xin Zhao Chao Wei shi-hua Yuan Science and Technology on Vehicle Transmission Laborator Bejing Institute of TechnologyBeijing 10081China

A new slip velocity model based on molecular potential theory and macro-force analysis,which is applied in Couette flow with pressure gradient,is built *** model is validated by later being introduced in hydrodynamic system to predict film distribution,which shows a good agreement with experimental data obtained from multi-beam intensity-based tests with Fe and Cu ball materials under accurate controlled temperature,load and different wall *** show that the slip length for Fe case is ignorable so it seems like no slip,but for Cu case,the slip length is large to make 20%discrepancy with no slip simulation and also behaves ***,during the experimental cases when both Fe and Cu ball velocities rise from-133 mm/s to 1330 mm/s,the slip velocity changes its direction with entrainment velocity and thus contributes to first enhance and then diminish the hydrodynamic film,but due to slip length on Cu case varying largely than that on Fe case,the film from Cu case and from Fe case has a clear cross-point between uh=80 mm/s and uh=220 m m/s(ub is the ball speed).The results above support strongly that Cu surface will lead to stronger slip than Fe case because of its smaller solid-liquid interaction,and obviously slip will influence hydrodynamic characteristics prominently.

关键词： Slip Couette flow with pressure gradient hydrodynamic characteristic

KAM Tori for the Derivative Quintic Nonlinear Schrodinger Equation

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Acta Mathematica Sinica,English Series 2020年第2期36卷 153-170页

作者： Dong Feng YAN Guang hua shi School of Mathematics and Statistics Zhengzhou UniversityZhengzhou 450001P.R.China College of Mathematics and Statistics Hu fnan Normal UniversityChangsha 410006P.R.China

This paper is concerned with one-dimensional derivative quintic nonlinear Schrodinger equation,iut—uxx+i(|u|4u)x=0,x *** existence of a large amount of quasi-periodic solutions with two frequencies for this equation is *** proof is based on partial Birkhoff normal form technique and an unbounded KAM *** mention that in the present paper the mean value of u does not need to be zero,but small enough,which is different from the assumption(1.7)in Geng-Wu[***.、53,102702(2012)].

关键词： Derivative nonlinear Schrodinger equation KAM theorem quasi-periodic solutions BirkhofF normal form

A molecular dynamics investigation of the deformation mechanism and shape memory effect of epoxy shape memory polymers

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Science China(Physics,Mechanics & Astronomy) 2016年第3期59卷 89-95页

作者： hua Yang Zheng Dao Wang Ya Fang Guo Xing hua shi Institute of Engineering Mechanics Beijing Jiaotong University State Key Laboratory of Nonlinear Mechanics Institute of Mechanics Chinese Academy of Sciences

Following deformation, thermally induced shape memory polymers(SMPs) have the ability to recover their original shape with a change in temperature. In this work, the thermomechanical properties and shape memory behaviors of three types of epoxy SMPs with varying curing agent contents were investigated using a molecular dynamics(MD) method. The mechanical properties under uniaxial tension at different temperatures were obtained, and the simulation results compared reasonably with experimental data. In addition, in a thermomechanical cycle, ideal shape memory effects for the three types of SMPs were revealed through the shape frozen and shape recovery responses at low and high temperatures, respectively, indicating that the recovery time is strongly influenced by the ratio of E-51 to 4,4'-Methylenedianiline.

关键词： shape memory polymer molecular dynamics simulation thermomechanics

In-vivo retinal imaging by optical coherence tomography using an RSOD-based phase modulator

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 607-612页

作者： Ling WANG Zhi-hua DING Guo-hua shi Yu-dong ZHANG State Key Laboratory of Modern Optical Instrumentation Zhejiang University Hangzhou 310027 China Institute of Optics and Electronies Chinese Academy of Sciences Chengdu 610209 China

Fourier-domain rapid scanning optical delay line (RSOD) was introduced for phase modulation and depth scanning in a time-domain optical coherence tomography (TD-OCT) system. Investigation of parameter optimization of RSOD was conducted. Experiments for RSOD characterization at different parameters of the groove pitch, focal length, galvomirror size, etc. were performed. By implementing the optimized RSOD in our established TD-OCT system with a broadband light source centered at 840 nm with 50 nm bandwidth, in vivo retina imaging of a rabbit was presented, demonstrating the feasibility of high-quality TD-OCT imaging using an RSOD-based phase modulator.

关键词： Optical coherence tomography (OCT) Phase modulation Retina imaging

Is ABP1 an Auxin Receptor Yet？

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Molecular Plant 2011年第4期4卷 635-640页

作者： Jing-hua shi Zhen-Biao Yang Center for Plant Cell Biology Department of Botany and Plant Sciences University of California Riverside CA 92521 USA

AUXIN BINDING PROTEIN 1 （ABP1） has long been proposed as an auxin receptor to regulate cell expansion. The embryo lethality of ABP1-null mutants demonstrates its fundamental role in plant development, but also hinders investigation of its involvement in post-embryonic processes and its mode of action. By taking advantage of weak alleles and inducible systems, several recent studies have revealed a role for ABP1 in organ development, cell polarization, and shape formation. In addition to its role in the regulation of auxin-induced gene expression, ABP1 has now been shown to modulate non-transcriptional auxin responses. ABP1 is required for activating two antagonizing ROP GTPase signaling pathways involved in cytoskeletal reorganization and cell shape formation, and participates in the regulation of clathrinmediated endocytosis to subsequently affect PIN protein distribution. These exciting discoveries provide indisputable evidence for the auxin-induced signaling pathways that are downstream of ABP1 function, and suggest intriguing mechanisms for ABPl-mediated polar cell expansion and spatial coordination in response to auxin.

关键词： Hormonal regulation hormone biology receptors signal transduction cell signaling.

New Exact Traveling Wave Solutions for Compound KdV-Type Equation with Nonlinear Terms of Any Order

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Communications in Theoretical Physics 2006年第5X期46卷 787-792页

作者： DU Xing-hua LIU Cheng-shi Department of Mathematics Daqing Petroleum Institute Daqing 163318 China

The compound KdV-type equation with nonlinear terms of any order is reduced to the integral form. Using the complete discrimination system for polynomial, its all possible exact traveling wave solutions are obtained. ... 详细信息

关键词： compound KdV-type equation complete discrimination system for polynomial traveling wavesolution evolution equation

Distribution of platinum group elements in road dust in the Beijing metropolitan area, China

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Journal of Environmental Sciences 2007年第1期19卷 29-34页

作者： WANG Juan ZHU Ruo-hua shi Yan-zhi Department of Chemistry Capital Normal University Beijing 100037 China

Dust samples collected from the Beijing metropolitan area （China） were evaluated to determine the distribution and the concentration of platinum group elements （PGEs）. The dust particles that were smaller than 100 mesh size fraction （150 μm） were analyzed after aqua regia digestion. Concentrations ofPt, Rh, and Pd were found to be between 3.96 and 356.3 ng/g, 2.76 and 97.11 ng/g, and 0.1 and 124.9 ng/g, respectively, in the urban areas of Beijing, whereas for the background samples collected from the suburbs of Beijing, the concentrations of Pt, Pd, and Rh were very low and ranged from 0.1 to 0.9 ng/g, 0.5 to 1.4 ng/g, and 0.8 to 2.2 rig/g, respectively. The distributions of PGEs in road dust were an accurate reflection of the levels of pollution and were found to match with the local traffic conditions. A strong positive correlation was established among all the dements found in road dust. This suggests that emissions of abraded fragments from vehicle exhausts may be the source of the high concentration of Pt, Rh, and Pd in road dust along the main roads of Beijing.

关键词： platinum (Pt) palladium (Pd) rhodium (Rh) road dust distribution environmental pollution